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Issue 109

December 2009

If you report a story, we ask that you credit Elsevier’s journal as the source.

Welcome to the 109th edition of Flash, our bi-weekly alert for science, health and medical journalists. Flash is a courtesy service with access to ScienceDirect, Elsevier’s online platform, providing full text access to some 2,000 scientific, technical and medical journals.

Please use your Flash login and password to access each article’s full text on ScienceDirect. For a new password, forgotten passwords or if you have any feedback, please contact Anna Hogrebe at newsroom@elsevier.com or at +31 20 485 3269.

ARTICLES

1. TEENS AND SEX – HOW DO EARLY ENCOUNTERS IMPACT FUTURE EDUCATION?

First love can be a powerful emotional. First lust can drive teens to the sexual fast lane. Beyond the broken hearts, mixed up feelings and sometimes sexually transmitted diseases and unwanted pregnancies, sex can change a person. But how do teens’ early sexual encounters impact their futures?

A new paper in Elsevier’s Journal of Adolescence uses longitudinal research to evaluate teen sexual debut may affect a teenager’s tertiary education in a UK setting. In addition to non-participation in college and university courses, it also examines earlier expectations for such education. Data were collected in three waves, spaced at two-year intervals (at mean ages 14, 16 and 18 years) with responses gathered from self-completed questionnaires.

Findings from this UK study found that sexual debut by age 16 was associated with reduced expectations for and participation in tertiary education, regardless of the level of academic achievement achieved at age 16. In fact, many sexually experienced teens opted out of tertiary education after leaving school early – including for reasons beyond pregnancy and partner pregnancy. The authors conclude that these results suggest that educators, policy makers and health professionals should take note of signals offered by early sexual debut for future academic achievement and explore ways to increase risk-taking teenagers’ engagement with school education.

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2. IMPLICATIONS OF THE LIANG BUA EXCAVATIONS FOR HOMININ EVOLUTION

Excavations at Liang Bua, on the Indonesian island of Flores, have yielded a stratified sequence of stone artifacts and faunal remains spanning the last 95 k.yr., including the skeletal remains of two human species – Homo sapiens and Homo floresiensis.

Expanding on the research on Homo floresiensis, better known as Hobbits, Elsevier’s latest Journal of Human Evolution looks at a more detailed analysis of the H. floresiensis skeletal remains and their context from deposits spanning approximately 95 ka to 17 ka. Specifically, they looked at the skull, teeth, brain endocast and postcranium, as well as the associated venivronmental setting, site geomorphology, stone artefacts, and faunal remains. The Liang Bua research team initially concluded that H. floresiensis may have evolved by insular dwarfing of a larger-bodied hominin species over 880 k.yr. or more. However, recovery of additional specimens and numerous primitive morphological traits seen throughout the skeleton suggest instead that it is more likely to be a late representative of a small-bodied lineage that exited Africa before the emergence of Homo erectus sensu lato. Homo floresiensis is clearly not an australopithecine, but does retain many aspects of anatomy that are probably plesiomorphic for the genus Homo. In fact, H. floresiensis bears no meaningful resemblance to human pygmies except for small body mass.

The authors hope this research will provide further evidence for the evolutionary history of H. floresiensis, and the nature and timing of early hominin dispersals in Asia.

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3. THE EFFECT OF CHEWING GUM ON SELF-REPORTED NICOTINE WITHDRAWAL: IS IT THE FLAVOUR, THE CHEWING OR A COMBINATION OF THE TWO?

The Centre for Disease Control estimates smoking has contributed to 12 million deaths over the past four years. From cancer to heart disease to respiratory illness, the risks are well-documented. Still, many smokers struggle to quit. Withdrawal symptoms can include irritability, depressed mood, insomnia and increased appetite. So what’s a smoker to do?

Chewing gum has been cited as one method to suppress symptoms associated with nicotine withdrawal. In Elsevier’s latest Addictive Behaviors a new study seeks to build upon this line of research by examining the impact of chewing gum on nicotine withdrawal severity over an extended period of nicotine abstinence. It also attempts to identify the specific attributes of chewing gum that may be responsible for the reported decreases in withdrawal. The act of chewing, flavour and the combination of the two were independently examined among 25 dependent cigarette smokers in three conditions – flavourless gum base, flavour strips and flavoured chewing gum. During the 24-hour abstinence period, participants were instructed to not use any other type of gum, mint or chewing candy.

Participants’ self-reported withdrawal across the abstinence period differed as a result of the product to which they were exposed. The gum with the flavour condition significantly lessened the severity of withdrawal compared to the flavourless gum base and control conditions, but not the flavour strip condition. Specifically, the flavoured gum condition was associated with the lowest reported levels of withdrawal, while the gum base condition was associated with the highest levels. These findings lend support to the notion that it is a combination of flavour and chewing that help reduce the severity of the symptoms of self-reported nicotine withdrawal.

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4. INFLUENCE OF THE HIJAB ON PERCEPTIONS OF WOMEN’S ATTRACTIVENESS AND INTELLIGENCE

The hijab, a head cover worn by Muslim women, has become an object of cultural debate in Western European countries in recent years, especially since 9/11. Taking a closer look at the perceptions associated with this piece of clothing, Elsevier’s latest Body Image explores how men perceive women’s intelligence and attractiveness when they wear this head covering.

Participants of the study included 98 British men – 57 self-reported non-Muslims and 41 Muslims. The men were presented with full-face greyscale photographs of five Caucasian and 5 South Asian women. Each of the women were photographed twice – once with their hair displayed and pulled back from their face, and second wearing a purple hijab covering their hair, neck and shoulders. All men were shown the images on a portable computer screen and then asked to rate the women for attractiveness and intelligence. The men additionally provided demographic details like age, ethnicity, religion and marital status for themselves.

Findings revealed the wearing of the hijab had observable effects on ratings of attractiveness and intelligence. Specifically, women wearing the hijab were rated significantly lower on attractiveness and intelligence than women not wearing the hijab. Results also showed that participant religion did not have a strong influence on ratings. The paper concludes by discussing these results in relation to religious stereotyping within increasingly multicultural societies.

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5. ETHANOL SPELLS TROUBLE FOR MAST CELLS, MAKING HUMANS MORE SUSCEPTIBLE TO INFECTIONS

Excessive alcohol use can do more than deliver a band hangover. It’s actually associated with an increased risk of infections and the development of certain tumours. This increased risk of infectious diseases has been attributed to ethanol-induced immunosuppression, as alcohol may impair the function of many cell types.

To explore the role of ethanol further when it comes to mast cell functions, Elsevier’s Life Sciences looks at both low and high concentrations of ethanol, as well as assesses whether or not ethanol can induce apoptosis in mast cells. Using human mast cell line (HMC)-1 cells, mouse bone marrow derived mast cells (mbMMC) and human peripheral blood derived mast cells (HuMC), researchers assessed the effects of both ethanol and acetaldehyde on mast cell proliferation. Apoptosis was assessed by measuring apoptotic nucleosomes and caspase-3, -8 and -9 activities using ELISA and Tunel assay.

The results of this study show that ethanol dose-dependently reduces the survival and proliferation of cultured rodent and human mast cells already at ethanol concentration. The reduced survival of cells was due to induction of apoptosis and was associated with increased activity of the caspase-3 and decreased Bcl-2/Bax ratio. At low ethanol concentrations, the death of mast cells was due to induction of apoptosis.

This research is important since mast cells may be critical in the first line of defence against bacterial infections in lung mucosa. The ethanol-induced mast cell apoptosis could in part explain the increased susceptibility to infections associated with excessive alcohol consumption.

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The Scirus tool bar makes it easier than ever to find scientific, technical and medical information on the Web and is quick and easy to install. After installing, the Scirus toolbar conveniently appears below your Internet Explorer address bar, meaning you have scientific searches at your fingertips, wherever you are on the Web. Link to Scirus: http://www.scirus.com/srsapp/toolbar/ If your browser does not support HTML, you may need to copy the links below and paste them into your browser to access the articles:
1. doi:10.1016/j.adolescence.2009.10.006
2. doi:10.1016/j.jhevol.2009.08.003
3. doi:10.1016/j.addbeh.2009.10.016
4. doi:10.1016/j.bodyim.2009.09.003
5. doi:10.1016/j.lfs.2009.09.004